A 10g bullet pierces the board. Bullet speed before impact 300 m / s, and after impact 200 m / s.

A 10g bullet pierces the board. Bullet speed before impact 300 m / s, and after impact 200 m / s. Find the work of friction force

These tasks: m (mass of the considered bullet) = 10 g (in SI m = 0.01 kg); V0 (velocity before impact) = 300 m / s; V (velocity after impact) = 200 m / s.

The work of the friction force acting on the bullet will correspond to the change in the kinetic energy of the bullet itself: A = | Ek2 – Ek1 | = | m * V ^ 2/2 – m * V0 ^ 2/2 |.

Let’s perform the calculation: A = | 0.01 * 200 ^ 2/2 – 0.01 * 300 ^ 2/2 | = 250 J.

Answer: The work of the friction force was 250 J.